[App_rpt-users] usb radio config file

[hwstar at rodgers.sdcoxmail.com]

> 
> From: "David Powell-Williams" <dpowellwilliams at shaw.ca>
> Date: 2010/01/05 Tue PM 03:26:26 PST
> To: <app_rpt-users at qrvc.com>
> Subject: [App_rpt-users]  usb radio config file
> 
> <snip>
> Second issue:  The loudest playback sounds cause the URI to go into
> saturation and distort. I may not have calibrated the levels very carefully,
> but even if I manually lower the txlevel setting from 800 down to, say, 300
> it still distorts - it's just a quieter distortion. What can cause this?
> <snip>
> 
> I have the same problem with a modified CM108 usb installation. 
> 
> After setting all the 'radio tune' parameters, there is serious distortion
> on voice modulation peaks, irrespective of the source being Iaxrpt or
> another node.  
> 
> However, the 'radio tune txvoice' generates a perfect sine wave at 3 KHz
> deviation, as seen on an oscilloscope at the exciter modulator or on a
> service monitor off-air.  I am using duplex=0 in rpt.conf since the node
> operates simplex.
> 
> Dave
> VE7MQ
> 2140
> 
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> 


I have not seen this on a properly configured system. Chances are it has to do with de-emphasis configuration on the receive side, or pre-emphasis/limiting (prelim) in the transmit side)

Where is the audio getting distorted? Transmit or receive?
so you see the distortion on the TX line or RX line if you look with a scope? 

You might be able to determine where it is getting distored by connecting your node to a working node you can monitor,  then send audio both ways.

Disclaimer: I offer URI support and suggestions as a courtesy only as I do not derive any income from sales of the URI. I am in no way obligated to provide support at any level.

Steve
WA6ZFT